The projects funded by this grant are designed to investigate the regeneration of sympathetic axons into the hippocampal formation of adult and neonatal rats following lesions of various afferent systems. The studies involve fluorescence histochemical analyses of growth patterns after fornix or combined fornix and entorhinal cortex lesions. These evaluate the role of deafferentation in determining the extent of sympathetic growth. Other studies evaluate the mode of termination of sympathetic fibers in the dentate gyrus using electron microscopy.